Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds genuinely new behavioral context the annotations do not carry: the data is read live on-chain and each call costs 0.0040 USDC, always paid. It stops short of covering freshness, failure modes, or rate limits, so not a 5.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences, zero filler, with the core capability front-loaded and the cost/payment condition appended last. Nothing could be cut without losing information.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

There is no output schema, so the description carries the return-value burden and does name the two returned values (supply APY, variable borrow APY). It omits units, response shape, and the meaning of "listed asset" for a non-default address, which is a modest but real gap.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100% for the single 'asset' parameter, so the schema already documents the ERC-20 address format and WETH default. The description merely restates "any listed asset (default WETH)" without adding format or constraint detail, so the baseline 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource: reads live Aave v3 reserve rates on-chain on Base, returning supply APY and variable borrow APY. Scope (which chain, which protocol version) and the returned quantities are explicit, making it easy to distinguish from siblings like liquidity-health or market-snapshot.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

"For yield and borrow-cost bots" implies the usage context but never states when to prefer this over alternatives such as liquidity-health or market-snapshot, and offers no exclusions or prerequisites. Usage is implied rather than guided.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.